255/40R19 · passenger car · PSI
What PSI for 255/40R19 tyres?
- Size
- 255/40R19
- Class
- passenger car
- Planning PSI
- 37
- Planning bar
- 2.55
psi
37
2.55 bar · 255 kPa · passenger car planning figure
255/40R19 · 37 psi · 2.55 bar · 255 kPa — estimates. Placard wins.
PSI is the garage-hose number. For 255/40R19 a typical passenger car planning figure is 37 psi cold — about 2.55 bar or 255 kPa. TPMS typically warns near 28 psi (about 25% below a 37 psi target). That is already a soft tyre. Low-profile {sz} does not want a “softer” pressure to recover ride. Stay at or slightly above the car’s original placard if load index is kept.
Estimated 255/40R19 pressure by load
These 255/40R19 load steps are ± a few PSI from 37. They are not a licence to ignore a printed second column on a van or estate.
| Condition | Front (est.) | Rear (est.) |
|---|---|---|
| Driver only / unladen | 37 psi / 2.55 bar / 255 kPa | 37 psi / 2.55 bar / 255 kPa |
| Typical occupancy | 38 psi / 2.62 bar / 262 kPa | 39 psi / 2.69 bar / 269 kPa |
| Motorway + luggage (sketch) | 39 psi / 2.69 bar / 269 kPa | 40 psi / 2.76 bar / 276 kPa |
PSI, bar and kPa
Use the table, then set a cold gauge. 255 kPa is 100 × 2.55 bar on this size.
| PSI | Bar | kPa |
|---|---|---|
| 33 | 2.28 | 228 |
| 34 | 2.34 | 234 |
| 35 | 2.41 | 241 |
| 36 | 2.48 | 248 |
| 37 | 2.55 | 255 |
| 38 | 2.62 | 262 |
| 39 | 2.69 | 269 |
| 40 | 2.76 | 276 |
| 41 | 2.83 | 283 |
| 42 | 2.90 | 290 |
| 43 | 2.96 | 296 |
| 44 | 3.03 | 303 |
| 45 | 3.10 | 310 |
| 46 | 3.17 | 317 |
| 47 | 3.24 | 324 |
| 48 | 3.31 | 331 |
| 49 | 3.38 | 338 |
What 255/40R19 means
Read 255/40R19 as width / aspect R rim. Nothing in the size string is a pressure. Pressure lives on the car, not moulded as 205 or 55.
EV 19-inch aero wheel. Rim diameter 19 in; section 255 mm. Estimates on this page assume a typical load index for the passenger car class.
Placard versus sidewall
The sidewall of a 255/40R19 may say 51 psi or 350 kPa. That is a carcass maximum. Operating pressure is the tyre-information placard on the driver’s door pillar.
Cars often seen on 255/40R19
These catalogue models are often seen on 255/40R19 or a close OEM neighbour. Open the vehicle chart for axle-specific PSI and bar.
How to set 255/40R19
- Park so the 255/40R19 tyres are cold (three hours, or less than about a mile).
- Read the door-pillar placard for that car — not the 255/40R19 sidewall maximum.
- If the sticker is missing, 37 psi / 2.55 bar is only a passenger car planning figure for this size.
- Set all four with a calibrated gauge. A 3 psi miss on one corner shows up as a wander.
- Refit valve caps and reset TPMS if the handbook asks for a relearn.
Temperature drift
Roughly 1 psi per 5–6 °C. The table uses 37 psi as a 20 °C baseline for 255/40R19.
| Ambient | Gauge | Bar | kPa | Note |
|---|---|---|---|---|
| −5 °C (hard frost) | 34 psi | 2.34 bar | 234 kPa | Gauge reads low; do not overfill once warm |
| 0 °C | 35 psi | 2.41 bar | 241 kPa | Gauge reads low; do not overfill once warm |
| 8 °C (UK winter morning) | 36 psi | 2.48 bar | 248 kPa | Gauge reads low; do not overfill once warm |
| 20 °C (set cold here) | 37 psi | 2.55 bar | 255 kPa | Baseline for this size sketch |
| 30 °C | 39 psi | 2.69 bar | 269 kPa | Do not bleed a hot 255/40R19 |
| 38 °C (heatwave tarmac) | 40 psi | 2.76 bar | 276 kPa | Do not bleed a hot 255/40R19 |
If the door sticker and this 255/40R19 page disagree, the sticker wins.
Questions about 255/40R19
Is the sidewall number correct for 255/40R19?
No. Sidewall PSI or kPa is a maximum for the carcass. Operating pressure is the door-pillar placard.
What is 255/40R19 in bar?
37 psi is 2.55 bar. Add a tenth of a bar if the placard’s laden column is higher, which is common on vans that wear this size.
Is 255/40R19 the same as a plus-size swap?
Only if that is the size you fitted. Overall diameter should stay close to OEM. Pressure still follows the car, with load index at or above original.
What PSI should 255/40R19 tyres be?
A passenger car planning figure is about 37 psi cold (2.55 bar / 255 kPa). Confirm on the vehicle placard — two cars can share 255/40R19 and not share a sticker.
Should I bleed pressure after a motorway run?
No. Heat raises the gauge. Set cold only. Bleeding a hot tyre leaves it low the next morning.
Handbook: placard · bar vs PSI · cold inflation · all sizes